Rheostat-arm mount



May 15, 1928. 1,669,687

H. E. ADAMS ET AL RHEOSTAT ARM MOUNT Filed July 1926 Patented May 15, 1928.

UNITED STATES PATENT OFFICE,

HARRY E. ADAMS AND HUGH L. DECKER, OF TOLEDO, OHIO, ASSIGNORS TO THE W. G.

NAGEL ELECTRIC COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO.

RHEOSTAT-ARM MOUNT.

Application filed July 16,

This invention relates to liquid lever indicators, and particularly to those of the type having a float actuated rheostat in connection therewith wherein a s\v.'nging contact arm is employed. Y

The object of the invention is the provision of simple, efficient and improved means for mounting or connecting the swinging rheostat arm to the actuating parts, whereby to facilitate adjustment of the arm relative to said parts for the purpose of calibration and to enhance the practicability and commercial value thereof.

The invention is fully described in the following specificat'on, and one embodiment thereof illustrated in the accompanying drawings, in which Figure 1 is a plane view of the upper end portion of a device embodying the invention, with the cover removed;

Figure 2 is an enlarged fragmentary sectionfon the line 22 in Figure 1;

Figure 3 is an enlarged perspective view of the rheostat contact arm removed from its carrying member; and

Figure 4 is an enlarged perspective view of the adjustable mounting means for the contact arm with the shaft of said means partly broken away.

Referring to the drawings, 1 designates a casing or frame forming, in the present instance, a substantially cylindrical chamber 2 containing the "segmental variable resistance unit 3 of the rheostat and having a central bearing in its bottom through which a shaft Sextends. The actuating means for this shaft, which is preferably of the float type, forms no part of thevpresent invention and therefore is not shown. A disc 6 is fixed centrally to the upper end of the shaft 5 and is disposed within the bottom of the chamber 2 eing heldslightly spaced from the bottomby a centrally raised portion 7 thereof.

A thin fiat member 8 preferably of sheet metal is mounted flat on the topof the disc 6 and forms a chair or holder for the body portion 9 of a swinging rheostat arm having a contact part 10 for engagement with the resistance unit 3 as the arm is swung.

The member 8 has an upstanding tongue 11 at .one side of its center which engages in a complemental recess 12 at the side of the arm body 9, which is opposed to the radially projecting contact part 10 thereof, and the member 8 is provided at it PP E ld 1926. Serial No. 122,780.

ber. When the parts of the rheostat are assembled, a spring contact finger 15 projects from a, terminal post at a side of the frame 1 over the top of the arm body 9 and bears downward against a center conducting post 16 of said body thereby acting to retain the arm body in its seat The center contact post 16 has electrical connection (not shown) with the contact member 10 of the arm. I

The chair 8 is broader than the arm body 9 to adapt it to project at its ends beyond the sides of the body, and each of these ends'is provided with segmental grooves 17 concen- V trio with the shaft 5 and adapted to receive a screw 18 that threads into the disc 6. It is thus evident that when the screwsj18 are loosened, the chair 8 and its arm may be rotatably adjusted within predetermined limits, determined by the length of the slots 17, and then securely clamped in adjusted relation to the disc 6 by a tightening of the screws.

This adjusting feature is important in instruments of this character as it enables the instrument to be easily, quickly and accurately calibrated, and is especially important where such instruments for float arms in geared connection with the shaft carry the rheostat arm. In such case, it is found in practice that in mounting the float rod or arm in the carrying frame 1 and meshing the gear on such arm with the companion pinion on the shaft carrying the rheostat arm it is not always possible to make the pinion and gear teeth register properly to bring the contact arm to the off position of the potentiometer when the float is at empty position. With the adjustment which is provided between the shaft 5 and the contact arm it is a very simple and easy matter to secure proper calibration of the parts. With the construction heretofore used, it was necessary to bend some of. the parts to give this correct registration,

tatable means carrying the holder and permitting rotary adjustment of one relative to the other.

2. In an instrument of the class described, a swinging rheostat arm having its length coextensive with the length of its swinging "radius, a holder for the. arm, a. rotatable member carrying the holder, and means for permitting relative rotary adjustment vof the holder and member and adapted to clamp them in adjusted relation.

3. In an instrument of the class described, a swinging rheostat arm, a holding member for the arm, a rotatable drive member supporting the holder-member, one of said members having segmental slots concentric to its turning axis, and means projecting through said slots and engaging the other member and'operable to clamp the members together or to release them for relative rotary adjust ment.

4. In an instrument of the class described, a rotatable member, a holder member carried by the rotatable member and having spaced parts projecting upward therefrom to adaptit to serve as a chair, a swinging arm carried by the chairand having a body portion engaged by the upwardly projecting parts ofthe chair to hold one against turning relative to the other, and means connecting the chair and rotatable member to permit relative rotary adjustment thereof and to clamp the same in adjusted relation.

5. In an instrument of the class described, a drive shaft, a plate fixedly carried by the shaft at its upper end, a-chair mounted on the plate for relative rotary adjusting movements relative thereto, a swinging rheostat arm carried by the chair for turning movct ments therewith, and means for securing the plate and chairin any position of rotary adjustment.

6. In an instrument of the class described, a drive shaft, an enlargement on the shaft having a substantially fiat top surface, a chair mounted on the enlargement for relative rotary adjusting movements and having spaced projections, aswinging rheostat arm having its inner end portion mounted on the chair and interengaged by the projections thereof to prevent relative turning movements of the chair and arm, and means for securing the shaft enlargement and chair in any position of rotary adjustment.

7. In an instrument of the class described, a drive-shaft having an enlargement at one end, a chair mounted on said enlargement for rotary adusting movements relative thereto and having spaced projections extending away from the enlargement, a swinging rheostat arm having its inner end portion mounted in said chair and engaged byfsaid projections to have turning movements with the chair but permitting relativeaxial disengaging movements of the chair and arm, and means for securing the shaft enlargement and chair in any position of rotary adjustment.

In testimony whereof we have hereunto signed our names to this specification.

HARRY E. ADAMS, HUGH L. DECKER. 

